Effect of iron oxide nanocluster on enhanced removal of molybdate from surface water and pilot scale test

Abstract

Abstract A novel combination of magnetic adsorptive and coagulative strategy which was applied to remove molybdenum (Mo) ions from surface water was investigated in this study. The ferromagnetic nanoclusters and ferromagnetic nanoclusters-ferric flocs composite coagulant were characterized in terms of typical properties, structure and morphological analysis (TEM, XRD, M – H hysteresis curves, particle size distribution). Different removal agents of Mo was investigated that the removal rate of Mo was ferromagnetic nanoclusters-FeCl 3 > FeCl 3 > AlCl 3 > TiCl 4 . Jar tests were employed to evaluate the removal performances. The coagulation performances of ferromagnetic nanoclusters-ferric flocs were compared under different pH conditions and dosages. Various factors influencing the removal of Mo(VI), e.g. pH, the dose of ferromagnetic nanoparticle, FeCl 3 , were conducted using a 3 3 full factorial design approach. The results show that the newly addition of ferromagnetic nanoparticles obviously had a trend to form cluster, especially magnetic force acted as a key role that may promote the formation of ferromagnetic nanoclusters. The better removal performance of Mo could be attributed to the co-effect of ferromagnetic nanoclusters and ferric flocs. Meanwhile, in order to satisfy the national drinking water criterion, the reinforce effect of ferromagnetic nanoclusters on reducing the concentration of ferric (Fe) ions in effluent makes sure that the content of ferric ions under 0.3 mg/L. The experimental results indicated that mechanism of the molybdate removal was a physical surface adsorption which might combine with chemical action.